Gear-grinding device



G. M. EATON GEAR GRINDING DEVICE Filed Oct. 27, 1925 WITNESSES: INVENTOR Patented Oct. 16,1928.

UNITED STATES PATENT OFFICE."

HOUSE ELEGTRIG & MANUFACTURING VANIA.

COMPANY, A. CORPOBATION OF PENNSYL- GEAR-enmnine DEVICE.

Application filed October 27, 1923. Serial No. 971,142.

My invention relates to gear grinding, more particularly to an abrasive element for grinding gear wheels by a generating process.

It is among the objects of my invention to provide an abrasive element constructed of a number of parts which shall adapt it particularly to a. certain class of work and which shall greatly reduce the cost of manufacture and the maintenanceof the abrasive material.

It is a further object of myinvention to provide an abrasive element of simple compact and durable mechanical construction in which the abrasive material shall be firmly secured and mounted on a less expensive sup porting member.

It is a still further object of my invention to utilize abrasive materials. of such shape, and in such manner as shall permit of adjustment to take up or make allowance for wear. 7 7

It has been heretofore proposed to utilize an abrasive element comprising a helical worm or screw member, for the grinding of the teeth of gear wheels by a generating process, in which the abrasive material is renewable.

My present invention is directed to an abrasive element for grinding gear teeth in which not only the working portion is renewable but the entire abrasiveportion of the element may be renewed in various ways.

My invention is particularly ada ted to the production of abrasive elements 0 relatively large sizes, which may be, for example, several feet in diameter and having fluted portions corresponding to the threads of hob cutters employed in generating gear wheels.

In accordance with my invention, I utilize a center support or hub member of suitable material, preferably cast iron, which is provided with a central opening by means of which it is mounted on a work spindle and I having an outer periphery of abrasive material which is secured thereto in .any suitable manner. I

This construction greatly reduces the cost of the grinding element sincethe relatively inexpensive metal is substituted for the solid abrasive element and since the amount of material replaced due to wear of abrasive is reduced to a minimum.

In the accompanying drawing constituting a part hereof and in which like characters designate like parts,

Fig. l is a view, partially in elevation and partially in cross-section, of an abrasive element embodying the principles of my invention,

Fig. 2 is a side elevational view of a fragmentary portion thereof,

Fig. 3 is an enlarged cross-sectional view showing means for mounting abrasive tooth segments on the supporting hub member, and

Fig. 4 is an end elevational view of a fragmentary portion of the supporting hub illustrating a modified form of abrasive segment mounted thereon.

A Referring to Fig. 1, the abrasive element shown there-in comprises a central supporting hub member 1 having a central opening 2 adapted to receive a work spindle 3 which is mounted for rotation. The hub member 1 is provided with radial spokes 4 carrying an outer rim portion 5 having a flanged edge 6.

reference The opposite edge of the rim is provided with a depending flange 7 having a plurality of threaded openings 8.

An abrasive member comprising a ring 9 having threaded projecting portions 10 formed integrally therewith, is mounted on the rim 5 against the flange 6 thereof and is secured thereon by an annular clamping plate 11 which is secured by a plurality of screw bolts 12 fitted into the openings 8.

Referring to Fig. 3, the abrasive material is substantially of keystone shape, the lower dove-tail portion 13 of which is secured in the rim 5 of the hub. In this instance one or more helical grooves 14 are formed in the outer periphery of the rim 5. The grooves are substantially dove-tail or trapezoidal in shape and a plurality of threaded openings 15 are provided in the bottom of the grooves for receiving adjusting screws 16. The abrasive teeth 10 are in segment form and are provided with liners 17 of sheet metal or other suitable material which is more ductile than the abrasive material to facilitate the handlingof the teeth members and to reduce breakage. The teeth are inserted in the groove 14 to form a helix or screw thread continuous over the length of the hob, each segment being contiguous-to its adjacent segment. The segments are secured in the grooves by means of the adjusting screws 16 which force the same against the inclined faces of the grooves 14.

The tooth segments are secured in their proper working positions by a strip 18 which may be in the form of a helical coil spring disposed in the groove 14 to distribute the pressure of the screws 16. The segments are all assembled in position in helical form and the screws 16 are drawn against the strip 18 in consecutive order to secure the segments consecutively around the entire helix.

In Fig. 4, I have shown still another modification in which the outer periphery of the rim 5 of the hub member 1 is provided with T- slots 19 parallel to its axis. The abrasive tooth segments 10 are shaped to the contour of the rim and are provided at their ends with seating portions 20 and with centrally depending T-shape portions 21 which are inserted in the slots 19. The segments may be held in place by a wedge 22 or set screws or any other suitable means.

It is evident from the above description of my invention that abrasive elements for grinding gear wheels made in accordance therewith will materially advance the devel opment of gear grinding by a generating process because of the simple construction which greatly reduces the cost of the grinding member. a

Although I have described a specific embodiment of my invention it will be obvious to those skilled in the art that various modifications may be made in the details of construction thereof such as in the manner of mountmg and securing the abrasive material on the hub portion without departing from the principles herein set forth.

I claim as my invention 1.- An abrasive device comprising a cylinder having a, helical groove, abrasive inserts said inserts therein.

contiguously mounted in said groove, metal liners for said inserts and means for securing 2. An abrasive device comprising a cylindrical support having a grooved outer periphery, abrasive material inserted in said groove, metal liners for said abrasive material and means for securing the same in said groove.

3. An abrasive device comprising a cylindrical support having a grooved outer periph- "ery, segments of abrasive material having metal liners thereon disposed in said groove, a flat helical strip intermediate sald liners and groove and means for expanding said str p.

4. An abrasive device comprising a cylindrical support having a grooved outer periphery, segments of abrasive material having metal liners thereon disposed in said groove,

a coil spring disposed in said groove inter mediate said segments and the bottom of the groove and means comprising a plurality of adjusting screws for expanding said spring against said segments.

5. An abrasive device comprising a cylin-.

drical support having slots disposed on the outer periphery thereof, segments of abrasive material disposed in said slots and seating means on said segments comprising metal liners for engaging said cylindrical support.

6. A gear-grinding hobcomprising a cylindrical support having a helical groove ofsubstantially trapezoidal cross section, abrasive inserts contiguously mounted in said groove, said inserts having bases corresponding to said grooves and working faces corresponding in contour to the spaces between adjacent gear teeth.

In testimony whereof, Ihave hereunto sub scribed my name this 20th day of October,

GEORGE M. EATON. 

